Aldehyde fixation on polymeric material



United States Patent 3,420,696 ALDEHYDE FKXATION 0N POLYMERIC MATERIAL James F. Cotton, Columbus, Ga., and Maurice E. Heard, Lanett, Ala, assignors to West Point-Pepperell, Inc, West Point, Ga., a corporation of Georgia N 0 Drawing. Continuation-impart of application Ser. No. 372,113, June 2, 1964. This application Apr. 26, 1965, Ser. No. 451,033 US. Cl. 117-118 36 Claims Int. Cl. Dtl6m /54; C083 1/44 ABSTRACT OF THE DISCLOSURE An aldehyde is fixed on a polymer of the group consisting of cellulose, cellulose esters and starch, comprising the steps of treating said polymer with an aqueous mixture containing a member of the group consisting of 1) an aldehyde together with a carbamate having the formula NCOORz where R and R are selected from the group consisting of hydrogen, alkyl and carbocyclic aryl, and R is selected from the group consisting of alkyl and carbocyclic aryl, (2) an aldehyde-carbamate condensation product wherein the carbamate has the formula H NCOOR and (3) an aldehyde together with an aldehyde-carbamate condensation product wherein the carbamate has the formula N NCOOR and heating said treated polymer at a temperature snfiicient to fix the aldehyde on said polymer but insufiicient to cause any substantial nitrogen fixation.

This application is a continuation-in-part of application Ser. No. 372,113, filed June 2, 1964 and now abandoned.

This invention relates to a novel and improved process for the fixation of an aldehyde on cellulose, cellulose esters and starch. It is known to fix aldehydes such as formaldehyde for example, on cellulose, cellulose esters and starch. It such prior art processes, however, it has been found diflicult to predetermine the amount of formaldehyde fixed, and to reproducibly control the amount of formaldehyde fixed. Also, in some instances, there is required the use of concentrated solutions of formaldehyde with high amounts of acid that tend to degrade the material being treated. Additionally, in such prior art processes, the efiiciency is low in the sense that only a small amount of the formaldehyde used is actually bound on the substrate, such as cellulose, the remainder being lost. The invention relates also to a novel aqueous formaldehyde composition.

It has previously been proposed to apply a precondensate of formaldehyde with an alkyl carbamate, e.g. formaldehyde-methyl carbamate precondensate, to cellulose. In such procedure, there is a fixation of the nitrogen of the precondensate to the cellulose molecule, as can be verified by the significant increase in nitrogen content of the treated cellulose over the relatively minor amount of nitrogen present in the untreated cellulose material.

It is a principal object of the present invention to durably fix an aldehyde, preferably formaldehyde, to cellulose, cellulose esters and starch. Yet another object is to provide an aldehyde fixation process in which the degree of aldehyde fixation is readily and precisely controllable and reproducible. The process is exceedingly eflicient, economical and rapid. The aldehyde is permanently fixed, proof against repeated washing.

Another object is to impart wash-and-wear properties and crease resistance to cellulose fabrics. A related object is to stabilize cellulose fabrics against shrinkage. The process is particularly advantageous in that it involves substantially less loss of strength than does conventional resin finishing, while achieving a high level of washwear performance.

Yet another object is to provide wash-wear fabrics cross linked with formaldehyde, which do not retain chlorine or otherwise discolor of pick up soil in the course of repeated washings. Related objects are to provide cellulosic fabrics which are mildewproof and rot resistant.

An additional object is to improve the permanent crease retention properties of cellulosic fabrics.

Another object is to increase the wet strength properties of paper.

Another object is to provide a novel formaldehyde composition, suitable for fixing and other purposes.

A still further object is to reduce the swelling tendency of cellulosic fabrics when wet with water or aqueous solutions, and especially of nonwoven viscose rayon fabircs.

Yet another object is to achieve better whiteness retention. Further objects will be in part evident and in part pointed hereinafter.

In accordance with the present invention, the foregoing objects can be attained by treating starch, cellulose or a cellulose ester with an aqueous mixture containing one of the following materials: (1) a mixture of an aldehyde and an alkyl carbamate, (2) an aldehyde-alkyl carbamate condensation product, (3) a mixture of an aldehyde together with an aldehyde-alkyl carbamate condensation product. In place of the alkyl carbamate in (1), (2) or (3) there can be used an aryl carbamate. There also can be used N-hydrocarbyl substituted alkyl or aryl carbamates. After the material is treated with the aqueous mixture, it is heated to a temperature sufiicient to fix the aldehyde on the cellulose or the like, but insufiicient to cause any substantial nitrogen fixation on the material treated. The cellulose can be in the form of cotton, alpha cellulose, regenerated cellulose or rayon, e.g. cuprammonium rayon or viscose rayon, or paper. As cellulose esters, there can be employed cellulose acetate, cellulose acetate-butyrate, and cellulose acetate-propionate. As the aldehyde, there can be employed formaldehyde, glyoxal, pyruvic aldehyde, glutaraldehyde, acetaldehyde, propionaldehyde, butyraldehyde and hydroxyadipaldehyde. The preferred aldehyde is formaldehyde.

The cellulose material can be blended with synthetic fibers such as polyesters, e.g. polyethylene terephthalate, acrylic fibers, e.g. polyacrylonitrile, acrylonitrile-vinyl chloride (:15; or 15:85), nylon, e.g. polymeric hexarnethylene adipamide, polypropylene, propylene ethylene copolymers, spandex, vinyl-chloride vinyl acetate, e.g. (87:13).

For special purposes where extra rigidity is required, it is desirable to employ glyoxal. When less rigidity than that imparted by formaldehyde is desired, other aldehydes such as acetaldehyde or hydroxyadipaldehyde can be used. Of course, mixtures of aldehydes can be employed.

The alkyl carbamate has the formula:

H NCOOR where R is an alkyl group. Thus, there can be employed methyl carbamate, ethyl carbamate, propyl carbamate, isopropyl carbarnate, butyl carbamate, amyl carbamate, hexyl carbamate, octyl carbamate, decyl carbamate, dodecyl carbamate, cyclohexyl carbamate and octadecyl carbamate. Mixtures of carbamates can be employed, e.g. the eutectic mixture of 52% ethyl carbamate and 48% methyl carbamate.

As aryl carbamates, there can be employed phenyl carbamate, o-tolyl carbamate, p-tolyl carbamate, m-tolyl carbamate, p-butylphenyl carbamate, a-naphthyl carbamate, B-naphthyl carbamate, 2,4-xylyl carbamate.

As N-hydrocarbyl substituted carbamates having the formula R NHCOOR where R and R are alkyl or aryl, there can be used N-phenyl isopropyl carbamate, N-phenyl phenyl carbamate, N-p-tolyl ethyl carbamate, N-phenyl methyl carbamate, N-phenyl ethyl carbamate, N-methyl phenyl carbamate, N-ethyl phenyl carbamate, N-methyl methyl carbamate, N-methyl ethyl carbamate, N-methyl decyl carbamate, N-ethyl methyl carbamate, N-ethyl ethyl carbamate, N-dodecyl methyl carbamate, N-butyl cyclohexyl carbamate, N,N-diethyl ethyl carbamate, N,N-dimethyl ethyl carbamate, N,N-diethyl methyl carbamate, N,N-diphenyl methyl carbamate.

Higher temperatures are generally required to activate the aryl carbamates and the N-hydrocarbyl carbamates than is the case with the lower alkyl carbamates such as methyl carbamate and ethyl carbamate. Hence, these latter compounds are usually preferred.

As indicated, there can also be employed an aldehydealkyl carbamate condensation product (or an N-hydrocarbyl carbamate or an aryl carbamate). Preferably, however, there is employed a mixture of the aldehyde and alkyl carbamate, since it has been found that the reaction proceeds more smoothly, and shorter process times are normally required. Additionally, the use of the mixture eliminates the expense of preforming the aldehydealkyl carbamate condensation product.

When utilizing an aldehyde-alkyl carbamate condensation product, it is important that the heating of the treated product be at a temperature not above about 300 F., because if a higher temperature, such as 350 F., is utilized, instead of the condensation product decomposing to form ammonia, carbon dioxide and an alcohol, the competing reaction of nitrogen fixation to cellulose through the methylol group tends to take place in accordance with prior art procedures.

On the other hand, when utilizing an aqueous mixture of an aldeyde and a carbamate, the temperature of heating the product in order to fix the formaldehyde to cellulose or the like can be varied much more widely. Thus, not only can temperatures of 180 to 300 F. be employed, but there can be utilized more elevated temperatures, such as 350 or 400 F.

Unless otherwise specified, throughout the specification and claims, the temperature of heating the product connotes the actual temperature to which the product is elevated, as determined for example by surface pyrometry or infrared pyrometry in the case of moving fabrics; as will be understood, this will normally correspond to a somewhat higher oven temperature, or the desired temperature level may be achieved by radiation from heat sources themselves at a considerably higher temperature. The apparent reason for this is that the reaction to form the methylol carbamate proceeds relatively slowly, whereas the reaction to fix the formaldehyde to cellulose or the like goes quite rapidly. Product temperatures of 180 300 F. are preferred, as less likely to degrade the product. A preferred cure or fixation temperature range for cotton is ZOO-220 F.

Surprisingly, it has been found that the carbamate acts only as a carrier in assisting the formaldehyde to become fixed on the cellulose or the like, but does not itself become fixed in any significant amount to the cellulose material being treated.

It has been observed that in order to aid in fixing formaldehyde or other aldehyde on cellulose or the like, there should be employed at least 0.1%, and more preferably at least 0.3% by weigt of methyl carbamate, for example, in the aqueous solution or dispersion, or equivalent molar percentage by weight of other carbamate used. It is difficult to maintain control of the amount of formaldehyde fixed to the cellulose if less than 0.1% of methyl carba- 4 mate or equivalent is in the solution or dispersion. For more control of the reproducibility of formaldehyde fixation, it is desirable to use at least 0.5% of methyl carbamate or equivalent in the aqueous system. Throughout the present specification and claims, unless otherwise indicated, all parts and percentages are by weight.

Higher amounts of carbamate, e.g., 1% to 5% or more by weight of methyl carbamate (or other carbamate) in water, can be employed, but normally there is no advantage in utilizing excess amounts since they do not appear to give better results than does 1% or so, which would justify the increased cost of the reagent. Preferably, the alkyl carbamate employed is a lower alkyl carbamate; most preferably methyl carbamate, ethyl carbamate and mixtures thereof.

The aldehyde is employed in the aqueous system in an amount normally between 1% and 8% thereof, although if relatively large amounts of formaldehyde are to be fixed onto the cellulose or other material, there can be used as much as 10% or or more of aldehyde. Desirably, the aldehyde is employed in an amount of at least 3 moles per mole of carbamate, and can be employed in an amount as much as moles or even moles per mole of carbamate. Generally, lower mole proportions of aldehyde are preferred, and one of the advantages of the present invention is that lower amounts of aldehyde are required in the aqueous treating system, for the amount of formaldehyde fixed on the cellulosic material, than is the case with prior art processes. Additionally, the problem of formaldehyde odor is thereby materially reduced.

When treating cotton, alpha cellulose, starch and paper, there is usually employed an aqueous solution containing 1.25-4.0% of formaldehyde, in order to fix 0.25- 1.25% formaldehyde, onto the treated material.

When treating rayon and cellulose esters, there is usually employed an tqueous solution containing 2.S-8.0% of formaldehyde, in order to fix 0.50-2.5% formaldehyde, onto the treated material. Of course, with any of the materials there can be employed a solution containing 1.25-8.0% of formaldehyde, to fix 0.25-2.5% formaldehyde, by weight of the treated material.

When employing a carbamate-aldehyde condensation product, there is preferably added to the solution enough aldehyde to bring the aldehyde level to at least 3 moles of aldehyde (including that in the condensation product) per mole of carbamate present in the condensate.

The mixture of aldehyde and alkyl carbamate, e.g. formaldehyde and methyl carbamate, can be shipped as an aqueous mixture containing the two materials in any of the proportions indicated above. This aqueous mixture can be relatively concentrated at the time of shipment and can then be diluted with water to obtain the desired amount of ingredients for the bath through which is passed the cotton, for example. For stability purposes, the mixture which is shipped is preferably neutral, although it can be alkaline or acidic.

The bath through which the cotton or other material is passed is generally acidic or has a latent acid catalyst therein. Suitable acids and latent acid catalysts include formic acid, hydrochloric acid, ammonium chloride, zinc nitrate, zinc chloride, zinc fluoroborate, or mixtures thereof. Since little catalyst is required, it may be supplied by residual acid-forming salt, such as ammonium chloride, on the goods being treated.

Fixation of an aldehyde on the material, utilizing the alkyl carbamate carrier has also been found to be operative on the alkaline side, e.g. using catalysts such as sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, sodium hydroxide or potassium hydroxide. For most purposes, acid catalysts are preferred. As in the former case, the alkaline catalyst may be supplied on the goods being treated. When catalyst is added to the treating bath, it is normally used in an amount of 0.1-2% of the bath, although this can be varied.

The normal procedure for applying the aldehyde and carbamate mixture to the material is to pass a fabric,

obtained with drying to a residual moisture content of 24% measured with a resistance type moisture measuring device. For very best results the fabric is carried to the point of substantially being bone dry.

fibers, sheet or continuous yarn through the aqueous miX- 5 The process of the present invention also imparts better ture of aldehyde and carbamate, and then to run the thus whiteness retention to cellulse fabrics, e.g. viscose rayon lmpregnated material through squeeze rolls to remove fabrics, cotton fabrics and fabrics containing blends of excess solution. In the case of yarn, the procedure may synthetic and cellulosic fibers. be to pass the solution through packages of the yarn in a The present invention is also important in greatly rekier. A similar process can be employed in treating 10 ducing the swelling properties of cellulosic fabrics. starch. This is particularly true in the case of viscose rayon, The process of the present invention has the advantage especially nonwoven viscose rayon fabrics. Consequently over prior art processes of fixing aldehyde to material the aldehyde and carbamate treatment of the present insuch as those described above, with good reproducibility vention not only gives a cellulosic product, e.g. viscose of results, particularly when the alkyl carbamate is present rayon, of reduced swelling properties, but concomitant in the treating mixture in an amount of at least about therewith yields improved stabilization against shrinkage. 0.5%. A further advantage is that any desired amount of aldehyde can be fixed to the cellulose or the like, simply i I by controlling the amount of aldehyde in the aqueous Generally, the border yarns 1n towels shrink more than i t the rest of the towel. In order to overcome this defect, Of e, ther can b dd d t th aqueous mi t a series of towel border cotton yarns were treated in a of aldehyde and alkyl carbamate (or aldehyde-alkyl carkier with an aqueous mixture containing 1% methyl barnate condensation product), conventional additives, carbamate, 0.5% magnesium chloride hexahydrate, 0.5% such as wetting agents, hand modifiers, softeners, lubrifofmlc acid, 12% Sodium Chloride, 017% of a dimethyl cants, brighteners, and the like. Polysiloxane oil (softener), and the amounts of formalde- While formaldehyde is preferably employed as such hyde indicated below. After the treatment with the aquein the aqueous mixture, it is possible to utilize sources ous solution, the yarns were dried at 200 F. The treated of formaldehyde such as paraformaldehyde, trioxane, and yarns were then woven into the borders of cotton towels hexamethylenetetramine. In the case of such materials, with the results indicated in the following table:

TABLE I Percent Formaldehyde Percent Nitrogen Molar Ratio Sample Formaldehyde; Yarn in Yarn in Yarn in Yarn in Border 1 Methyl Finished Towel Finished Towel Pull-in in carbamate Towel Laundered Towel Laundered Launders 30 Times 30 Times Percent 2.51;1 0.14 0.13 0. 03 0.05 3.1 5. 0:1 0. 2s 0. 30 0. 05 0. 05 -0. 2 7. 5:1 0. 56 0. 56 0. 07 0. 07 0. 8 10.011 0. 77 0. 72 0.08 0. 04 -1.9 12. 5:1 1.13 0. 95 0. 07 0. 07 -1. 2 2. 511 0.16 0.16 o. 04 0. 03 1. 0 Untreated Control 0.03 0.07 6. 3

(Treated Yarn Average) 0. 058 0. 052

1 Border Pull-in Width of towel bodyWid-th of towel border X100 (i.e., dilferential shrinkage).

width of towel body A precondensate of methyl carbamate and formaldehyde was employed,

however, there is a slight lengthening of the overall time of the process in order to permit the breakdown of these materials to monomeric formaldehyde. For maximum efliciency, it has been found that a mole ratio of formaldehyde to alkyl carbamate of about 12.5 :1 gives best results. The present process is simpler to operate than the prior art procedures, and furthermore has the advantage that it is unnecessary to employ therein concentrated acid solutions or the like which are not only difficult to work with, but furthermore degrade the material.

An outstanding advantage of the process resides in the circumstance that formaldehyde may be fixed on the base material, for example on cotton yarn or fabric, with considerable reduction in loss of strength as compared with conventional resin finishing processes. In the latter, loss of to of original strength is common, and may exceed 50%. This sizable loss in strength is commonly compensated for by providing extra strength (and material) in the greige goods, at added cost. In the present process, the loss of strength is commonly only 15-25% and rarely over 30%. It is believed that this favorable result is due primarily to three circumstancesthe low temperature of drying that is required to fix the aldehyde, as compared to the high temperatures of normal resin curing conditions, the low concentration of catalyst used, and the fact that drying need not be carried to the end point of zero moisture content. Excellent results have been TABLE 2 Skein Percent Single End Percent Sample Breaking Retention Break, lb. Retention Strength, lb.

314 76 5. 20 69 208 72 5. 32 71 306 74 5. 33 71 316 77 5.37 72 316 77 5. 63 263 64 5.07 68 7 (Control) 411 7. 48

The strength retentions appearing above were based on bleached, mercerized yarn taken immediatel before treatment with methyl carbamate and formaldehyde. When the strength retention calculation is based on the greige, mercerized yarn (6.37 lb. single end break), the state at which yarn strength is normally determined, strength retention of the above yarns is from 80 to 88 percent.

7 EXAMPLE II Cotton yarn in a kier was saturated with an aqueous mixture containing 0.5% magnesium chloride hexahydrate, 0.5 formic acid, 0.3% methyl carbamate and the indicated amounts of formaldehyde. The yarns were then vacuum extracted and dried at 180 F. to 2-3% residual moisture.

TABLE 3 Percent Percent Molar Ratio Sample Formaldehyde Formaldehyde Formaldehyde to in Mix on Scoured Yarn Methyl Carbamate The amount of fixed formaldehyde on the yarn is usually about 20 to 25% of the formaldehyde content of the aqueous mixture.

EXAMPLE III An aqueous mixture containing 5% formaldehyde, 1% methyl carbamate and 1% magnesium chloride hexahydrate was padded on a bleached enameling duck at 55-60% wet pickup. The fabric was barely dried at 180 F. (about moisture), and heated at the indicated temperatures and times.

TABLE 4 Percent Appearance Warp Tempera- Time, Formalde- Percent Rating 2 Shrinkage, ture, min. hyde 1 Fixed Nitrogen Percent F. on Fabric on Fabric 5L 20L 5 0 52 0.07 4.0 3. 5 4. 3 4. 1 3 0 47 0.08 3. 0 4.0 2.8 2. 5 2 O 50 0.08 3. 5 4. 0 2.4 2.1 1 0 57 0. 09 4.0 4.0 1.0 2.0 0.58 0.09 3. 5 3.0 3.3 3. 5 Control 0.04 r. 8.3

1 Fabric scoured one hour at 200 F. in 0.25% chip soap and 0.50% soda ash, followed by thorough rinsing.

1 Determined on fabric laundered five and twenty tunes in an auto inatic washer with a rated capacity of 8 lbs. Fabric load was 8 lbs; wash temperature was 105 F.; fabric was tumbled dried in an automatic clothes dryer. Rated on AATCC 5 (best) to 1 (poor) scale.

EXAMPLE IV In another set of samples using a mercerized and bleached 136 X 64 cotton broadcloth, an aqueous solution containing 2.5% formaldehyde, 1.0% methyl carbamate and catalyst as noted was applied at 60% wet pickup. The fabric was barely dried at 180 F. (about 10% moisture) and heated at 260 F. for 3 minutes.

1 Fabric scoured one hour at 200 F. in 0.25% chip soap and 0.50% soda ash followed by thorough rinsing.

2 Estimated. Bath was neutralNH4Cl residual from preceding treatment of fabric.

Again only traces of nitrogen were found in the treated fabric, but it is important to note that the carbamate is not present on the fabric immediately after heating. This may be a clue in the determination of the mechanism of the reaction, because the carbamate is evidently decomposed by heating. A number of other samples have confirmed this observation.

EXAMPLE v Bleached, mercerized cotton yarn was treated in a kier with an aqueous solution containing 2.5% formaldehyde, 1.36% sodium chloride, 0.5% magnesium chloride hexahydrate, 0.5% formic acid, 0.1% dimethyl polysiloxane oil and the indicated amounts of methyl carbamate, and later dried at F.

TABLE 6 Mole Ratio Percent Percent Sample Formaldehyde Methyl Formaldehyde to Methyl Carbamate Fixed Garbamate EXAMPLE VI A bleached, mercerized cotton yarn in a kicr was treated with an aqueous solution containing 1.3% sodium chloride, 0.5% magnesium chloride hexahydrate, 0.5% formic acid, 0.1% dimethyl polysiloxane, 0.3% methyl carbamate and the indicated amounts of formaldehyde. The treated yarn was dried at 180 F.

TAB LE 7 Mole Ratio Percent Percent Sample Formaldehyde Formaldehyde Formaldehyde Carbarnate in Solution Fixed EXAMPLE VII Mercerized cotton yarn was treated in a kier with an aqueous solution of the indicated amounts of materials and dried at 200 F. The methyl carbamate-formaldehyde precondensate was the condensation product of 2.5 moles of formaldehyde with 1 of methyl carbamate and is indicated in the table by MC-F. There was also present in the aqueous solution 0.5 of polyethylene softener and 0.1% and alkylphenol-ethylene oxide condensate as a wetting agent.

TABLE 8 Sample Material MC-F, percent 4 8 4 4 MgCl -H O, percent. 1 1 1. 5 Zll(BF.i)2, percent 1 HGOOH, percent 1 1 1. 5 1

GHQO fixed, percent 0.63 1 93 1 02 0.78

No fixed nitrogen was observed in the yarn.

EXAMPLE VIII Both bleached, mercerized yarn and carded bleached cotton yarn were treated in a kier with an aqueous solution containing 2% of a methyl carbamate-formaldehyde precondensate (mole ratio 1:2.5), 2.1% free formaldehyde, 0.5% magnesium chloride, 0.5% formic acid, 2.5% sodium chloride, 0.2% sulfonated tallow (softener) and 0.025% of dimethyl polysiloxane. The yarns were dried at 200 F. The mercerized yarn picked up 0.72% fixed formaldehyde and the carded yarn 0.70% fixed formaldehyde.

EXAMPLE IX Mercerized cotton yarn was treated in a kier with an aqueous solution of 0.5% ethyl carbamate, 2.1% formaldehyde (mole ratio formaldehyde to carbamate of 12.5 :1), 0.5 magnesium chloride and 0.5 formic acid. The yarn was dried at 200 F. to fix the formaldehyde to the yarn.

The ability of the carbamate-formaldehyde process of the present invention to reduce swelling of fabrics is shown in the following examples in the treatment of needle punched nonwoven rayon fabrics.

Thus, a fabric which consists of an 8 oz. viscose rayon nonwoven web (Avril) needled into a 1.6 oz. polypropylene scrim, calendered and palmered had an objectionable tendency to swell and increase in gauge during wet processing. This objection can be overcome in part by using a combination of polypropylene fiber and viscose rayon for the web. Because of the thermoplasticity of the polypropylene, this combination of fibers in the web can be hot calendered and palmered to reduce the gauge of the base fabric and to reduce swelling and gauge increase during predipping. However, this fabric still swelled and increased in gauge on wetting. Furthermore, the inclusion of the polypropylene fibers was a relatively expensive solution to the problem.

EXAMPLE X Percent Methyl carbamate 1 Formaldehyde 4 Magnesium chloride 0.83

Formic acid 0.83 Nonylphenol ethylene oxide adduct (wetting agent) 0.2

This mixture is called Formulation A hereinafter.

Formulation A was applied at 120 F. in a laboratory padder. Fabrics (a) and (b) were dried in a continuous oven at 250 F. and fabric (c) was dried in the oven at 220 F. the fabrics were rolled up and held in a convection oven at 220 F. for 1 /2 hours to simulate conditions obtained if the fabric should be wound up hot in commercial production. Thermocouples embedded in the fabric rolls indicated the temperature on the inside of the fabric roll to be:

F. When placed in the oven 125 After 25 minutes 170 After 45 minutes 185 After 1 hour and 30 minutes 200 The gauges of these fabrics, before and after treatment, were measured with a Starrett Model 1010 spring loaded hand micrometer with a A inch anvil and /4 inch foot. The gauge was also measured after wetting in water.

Percent Fixed Gauge Gauge Formaldehyde (dr mils (saturated in water), mils Fabric (a) not treated. 40 68 Fabric (a) treated.-. 0.66 45 59 Fabric (b) not treate 0 40 41 Fabric treated 0. 51 34 36 Fabric (0) not treated 0 22 29 Fabric (0) treated 0. 56 23 25 The treated sample in each pair had an appreciably lower wet gauge than did the fabric not treated. The treatment also caused further compression and restriction of fabric (b), a fabric which as constructed was devised to restrict swelling. The formaldehyde fixation in this and the following examples is based on the total weight of the fabric.

EXAMPLE XI The fabric employed was 8 oz. viscose rayon web needled into a 1.6 oz. polypropylene scrim, calendered and palmered.

Formulation A (see Example X) was applied to one section of the fabric on a laboratory padder. One portion of this section was vacuum extracted between the top roll of the padder and the fabric wind-up. A second portion of this section was not vacuum extracted. Another section of the fabric was untreated. The fabrics were dried continuously in a laboratory oven at 250 F. A radiation pyrometer (Infrascope) indicated the fabric temperature at the exit to be 221 F. for the fabric vacuum extracted and 218 F. on the fabric not vacuum extracted.

The results of swelling tests on these fabrics were as follows:

Percent Gauge Gauge Fixed Gauge Saturated Saturated Formal- (dry), With 10 a dehyde mils Water, NaOH,

mi mils Not Treated 0 39 50 70 Treated 0. 51 48 47 Vacuum Extractedlreated 0.68 49 48 60 The apparent slight decrease in gauge of the two treated fabrics is illusory since the results are the averages of ten readings and the variation is about :2 mils.

EXAMPLE XII Formulation A (see Example X) Formulation B (the same as Formulation A, except it contained 8% of formaldehyde) Formulation C (the same as Formulation A, except it contained 2% methyl carbamate and 8% formaldehyde).

The formulations were all applied at room temperature in a laboratory padder and vacuum extracted.

The fabrics were dried in a laboratory continuous dryer set at 260 F. The fabric treated with Formulation A attained a surface temperature of 232 F., the fabric treated with Formulation B attained a surface temperature of 214 F., and the fabric treated with Formulation C attained a surface temperature of 210 F. These differences in temperature had an influence on the level of formaldehyde fixed in the fabric.

After drying, these fabrics were treated with sodium bisulfite solution to remove formaldehyde odor and recatalyzed with an aqueous mixture containing 0.83% each of MgCl and formic acid. The fabrics were then dried to the touch in a 300 F. oven after the washing and recatalyzation.

The fabrics were hot calendered on a two-roll calender at 250 F. and then palmered two passes at 260 F. on one drum of a two-drum compressive shrinkage machine.

The swelling effect was determined as in Examples X and XI by gauging the fabric dry, saturated with water and saturated with NaOH solution. Swelling characteristics were checked as finished in the laboratory (before 1 1 calendering), after calendering and after calendering and palmering. The results of these tests and of formaldehyde analyses are set forth in the following table:

based fabric softener was applied and dried into the fabrics, and the fabric was passed through a compressive shrinkage machine.

Percent. Gage Guage Guago Fabric Formulation Fixed (dry), Saturated Saturated CIIzO mils With Water, With 20% mils NaOH, mils (a) Not treated 42 54 70 (n) AB efore calenderc 0. 72 47 48 58 (a) ACalendered 36 47 54 (a) A-Calendered and palmered- 0. 77 36 45 54 (a) BBefore calendered 0.60 45 47 58 (a) B-Calendered 36 47 53 (a) BCalendered and palmeretL 0.47 32 44 56 (a) C-Before caleudered 0. 56 45 47 57 (a) CGalcndered 41 47 54 (a) CCalendered and palmer 0.45 34 47 62 (b) Not treated 0 62 58 08 (b) ABefore calcndered 0.44 53 55 54 (b) ACalendered 40 43 45 (h) A-Calendered and palmered 0. 46 40 40 47 (c) Nt-t treated 0 Z8 32 42 (c) ABeiorc calendercd. 0.53 30 30 36 (c) ACalendered 28 2t) 34 (e) A-Calendered and palmered 0.46 25 26 35 It is clear that the tendency of all of these fabrics in Example XII to swell in either water or in 20% NaOH has been reduced. Fabric (b) not treated, Gauge (Dry) is an artificially high value because this particular fabric was in the fiulfy condition. If it were in the normal compressed condition of the other fabrics, it would have had a gauge considerably below 58.

For significant reduction in the swelling of the fabrics, the fabrics usually contain a substantial amount of cellulose fibers, e.g. or more, usually at least Examples XIII and XIV demonstrate the speed at which processing of fabric is possible. They also demonstrate the rapidity of the reaction which occurs under very favorable conditions.

EXAMPLE XIII Three lightweight white fabrics containing blends of 65% polyester fiber and cotton fiber were processed through an aqueous mixture containing 1.0% methyl carbamate, 6.0% formaldehyde, 0.83% magnesium chloride, 0.83% formic acid, 0.5% acrylic polymer, comprising ethyl acrylate, methyl methacrylate, acrylic acid and acrylamide (Rhoplex E-32), 0.25% polyvinyl alcohol and 0.2% nonyl phenol-ethylene oxide condensate (wetting agent) followed by drying.

The three fabrics included:

(a) A 125 x 72 3.70 yards/lb. (greige count and Weight) broadcloth,

(b) A 96 x 84 4.25 yards/lb. (greige count and weight) batiste,

(c) A 94 x 80 4.34 yards/lb. batiste.

The polyester in fabrics (a) and (c) was Dacron, and in fabric (b) was Kodel.

The wet pick-up by these fabrics when passed through the mix on a padder was in the range of 35 to Drying was accomplished on a tenter dryer with the air temperature regulated at 330 F. The speed of processing was 110 yards/ minute and the fabric dwell time in the dryer was 14 seconds.

Fabric temperatures obtained as indicated by an infrared pyrometer (Infrascope) were in the range from 245 to 255 F.

After drying, the fabrics were padded through a sodium bisulfite solution to remove unreacted formaldehyde and obviate undesirable odors in the finished fabric (see US. Patent No. 2,870,041), washed and dried, a fatty acid (greige count and weight) The fabrics were found to have fixed formaldehyde levels as indicated which remained essentially constant through multiple laundering.

Percent formaldehyde found I Fabric Sample After 5 After 5 After 5 As finished 2 home sanlorize commercial launder-s 3 washes 4 white washes 5 conditions.

EXAMPLE XIV The three fabrics of Example XIII were passed through a mixture containing 1.0% methyl carbamate, 4.0% formaldehyde, 0.83% magnesium chloride, 0.83% formic acid, 0.5 acrylic polymer (Rhoplex 13-32), 0.7% fatty acid based softener and 0.2% nonyl phenol-ethylene oxide condensate (wetting agent).

These fabrics were dried under similar conditions to those in Example XIII, except that the speed was yards/minute and the fabric temperature as indicated by an infrared pyrometer was in the range from 250260 F.

These fabrics were processed after treatment as in Example XIII with bisulfite and softener, except that the mixture including the softener also included 1.4% MgCl and 1.4% HCOOH.

These fabrics were just barely dried after application of the mixture containing MgCl and HCOOH to prevent excessive loss of the acid.

These fabrics had the properties of the fabrics of Example XIII and also had the ability to retain a sharp crease after pressing and laundering. Thus, swatches of the fabrics were creased by pressing 15 seconds at a steam pressure of p.s.i.g. in a Forse laundry press. The creases remained sharp and smooth throughout multiple laundering.

This example demonstrates that the present invention can be utilized to impart durable shape retention and durable press to treated fabrics.

EXAMPLE XV A heavy (8.6 oz./ sq. yard) all cotton twill fabric which was previously mercerized and dyed was passed through an aqueous mixture containing:

1.0% methyl carbamate 4.0% formaldehyde 0.83% MgCl 0.83% HCOOH 1.0% acrylic polymer (Rhoplex E-32) 0.5% polyvinyl alcohol 0.2% nonyl phenol-ethylene oxide condensate (wetting agent) The fabric was dried in a tenter dryer set at air temperature of 330 F. The fabric temperature was 230 F. as measured by an infrared pyrometer. Dwell time in the oven was 21 seconds.

The fabric was then passed through an aqueous buffered catalyst mixture containing:

0.83% MgCl 0.83% HCOOH 0.50% Na S O (sodium meta bisulfite) 2.5% emulsified tallow softener The fabric was dried in a tenter dryer set at an air temperature of 250 F. The fabric temperature was 190 F.

Swatches of the fabric were creased by pressing in a steam heated laundry press for 15 seconds at 100 p.s.i.g. steam followed by heating in a convection oven set at 325 F. for six minutes.

When these fabrics were given multiple washings, the creases were retained and appearance of the fabrics was excellent.

Similar results were obtained when the pressed fabrics were placed in a convection oven at 275 F. for six minutes.

As indicated in Example XV, for crease retention it is desirable to add further catalyst to compensate for the catalyst lost in the initial heating employed to dry the formaldehyde treated fabric. The crease retention properties are then imparted after the initial cure of the fabric.

What is claimed is:

1. A process of fixing an aldehyde on a polymer of the group consisting of cellulose, cellulose esters and starch, comprising the steps of treating said polymer with an aqueous mixture containing a member of the group consisting of an aldehyde together with a carbamate having the formula where R and R are selected from the group consisting of hydrogen, alkyl and carbocyclic aryl, and R is selected from the group consisting of alkyl and carbocyclic aryl, there being at least 2.5 moles of aldehyde per mole of carbamate.

2. A process according to claim 1 wherein the aldehyde is formaldehyde.

3. A process according to claim 2 wherein R and R are hydrogen and R is alkyl.

4. A process according to claim -1, wherein the aqueous treating mixture includes an acidic catalyst.

5. A process according to claim 1, wherein the aqueous treating mixture includes a latent acidic catalyst.

6. A process according to claim 1, wherein the aqueous treating mixture includes a basic catalyst.

7. A process of fixing formaldehyde on a polymer of the group consisting of cellulose, cellulose esters and starch, comprising the steps of treating said polymer with an aqueous mixture of formaldehyde and an alkyl carbamate, and heating said treated polymer to fix the formaldehyde on said polymer.

8. A process according to claim 7 wherein the alkyl carbamate is a lower alkyl carbamate.

'9. A process of fixing formaldehyde on cellulose, comprising the steps of treating cellulose with an aqueous mixture of formaldehyde and an alkyl carbamate, and heating said treated cellulose to fix the formaldehyde on the cellulose.

10. A process according to claim 9 wherein the alkyl carbamate is a lower alkyl carbamate.

11. A process according to claim 10 wherein the alkyl carbamate is used in an amount of at least 0.1% up to 5% of the aqueous mixture.

12. A process according to claim 9 wherein the formaldehyde is used in an amount of from 3 to 60 moles per mole of carbamate.

13. A process according to claim 12 wherein the carbamate is methyl carbamate.

14. A process according to claim 13 wherein the heating is at a temperature of 180 to 300 F.

15. A process according to claim 12 wherein the carbamate is ethyl carbamate.

16. A process according to claim 15 wherein the heating is at a temperature of 180 to 300 F.

17. A process according to claim 9 wherein the cellulose is cotton.

18. A process according to claim 9 wherein the cellulose is regenerated cellulose.

19. A process according to claim 9 wherein the degree of formaldehyde fixation on the cellulose is from 0.25 based on the weight of the cellulose, and the cellulose is in the form of cotton.

20. A process according to claim 9 wherein the degree of formaldehyde fixation on the cellulose is from 0.5:2.5% based on the weight of the cellulose, and the cellulose is in the form of regenerated cellulose.

21. A product prepared by treating a polymer of the group consisting of cellulose, cellulose esters and starch with an aqueous mixture of formaldehyde and an alkyl carbamate, the canbamate being employed in an amount of 0.1% to 5% of the aqueous mixture and heating the treated polymer to fix the formaldehyde thereon.

22. A product according to claim 21 wherein the polymer is regenerated cellulose.

23. A product according to claim 21 wherein the polymer is cotton.

24. A product according to claim 22 wherein the regenerated cellulose is viscose rayon.

25. A process of reducing the swelling tendency of cellulosic fibers in an aqueous medium comprising the steps of treating said fibers with an aqueous mixture containing a member of the group consisting of an aldehyde together with a carbamate having the formula NCOOR2 where R and R are selected from the group consisting of hydrogen, alkyl and carbocyclic aryl, and R is selected from the group consisting of alkyl and carbocyclic aryl, the formaldehyde being 3 to 60 moles per mole of car- 'bamate.

26. A product prepared by the process of claim 25.

27. A process according to claim 25, wherein the aldehyde is formaldehyde and the carbamate is an alkyl carbamate.

28. A process according to claim 25, wherein said fibers comprise a substantial percentage of regenerated cellulose fibers.

29. A process according to claim 25, wherein said fibers comprise at least 35% viscose rayon fibers.

30. A process according to claim 25, wherein the alkyl carbamate is methyl carbamate.

31. A process of fixing an aldehyde on a fabric comprising fibers of a polymer of the group consisting of cellulose and cellulose esters, comprising the steps of treating said fabric with an aqueous mixture containing a member of the group consisting of an aldehyde together with a carbamate having the formula NCOORz R1 where R and R are selected from the group consisting of hydrogen, alkyl and carbocyclic aryl, and R is selected from the group consisting of alkyl and carbocyclic aryl to obtain a shape and crease retentive fabric, there being at least 2.5 moles of aldehyde per mole of carbamate.

32. A process according to claim 31 wherein the aidehyde is formaldehyde.

33. A process according to claim 31 wherein R and R are hydrogen and R is lower alkyl.

34. A process according to claim 31, including the further step of adding additional catalyst to the treated fabric, drying the further catalyzed fabric and pressing and heating the fabric to obtain a shape and crease retenti ve fabric.

35. A process according to claim 34, wherein said catalysts are acidic catalysts.

36. A product prepared by the process of claim 31.

References Cited UNITED STATES PATENTS 3,144,299 8/1964 Prick et a1 8116.3 3,160,469 12/1964 Vail et a1. 1l7-114 X 3,219,632 11/1962 Prick et a1. 26072 WILLIAM D. MARTIN, Primary Examiner. THEODORE G. DAVIS, Assistant Examiner.

US. Cl. X.R. 

